1. Field of the Invention
The present invention relates to a smart key system.
2. Description of the Related Art
Recently, a system (hereinafter, referred to as “smart key system”) which enables the locking and opening of doors or a fuel tank cap of a vehicle as well as permission for engine starting without using a mechanical key has been developed. In this smart key system, wireless communication is performed between a portable electronic key which is carried by a user (hereinafter, referred to as “electronic key”) and a control device mounted in a vehicle. When a request from a regular user is confirmed by checking the ID data of both sides, the starting of the engine is permitted, for example. In addition, the smart key system is also adopted in two-wheeled vehicles as well as four-wheeled vehicles, and the like.
Further, for example, a communication system by means of a non-contact medium such as a Speed pass (registered trademark) and the like has been used for settling accounts at self-service gas stations or various kinds of eating establishments or the like in recent years. Settlement is made simply by placing the non-contact medium over a reader installed at the gas station or the eating establishment, and thereby the convenience thereof becomes higher.
However, a frequency of a radio wave (for example, 134 kHz) used in the Speed pass (registered trademark) is close to that of a radio wave (for example, 125 kHz) used in the smart key system, and thus the radio wave of the Speed pass (registered trademark) may become a disturbance in a radio wave (for example, a request signal) which is output to the electronic key from a transmitter circuit of the control device mounted in the vehicle. As a result, there is a problem in that authentication of the smart key system is not instantly performed and thereby a time lag for the authentication occurs and the like. In this case, a user cannot determine the disturbance resulting from the Speed pass (registered trademark) as the cause thereof, and may thus feel displeased and incorrectly believe the electronic key to be out of order or the like.
Therefore, in order to counter this, a keyless entry device is provided in which when there are a plurality of communication frequencies and interference is generated in a currently set reception frequency, a transmission frequency of a portable device and a reception frequency of a vehicle-mounted device are changed by operating a frequency setting operation unit so as to cancel the interference (for example, see Japanese Unexamined Patent Application, First Publication No. 2005-299305).
In the conventional technique described above, however, the communication frequency of the keyless entry device is changed, therefore a transmission frequency setting unit for changing a transmission frequency is required to be provided in the portable device and, further, a reception frequency changing unit for changing a reception frequency is also required to be provided in the vehicle-mounted device. Thereby, there is a problem in that circuit configurations of both of the portable device and the vehicle-mounted device become complicated.
Therefore, the present invention was made to solve the problems and an object thereof is to provide a smart key system capable of promptly performing an authentication of a portable electronic key by means of a control device with a simple configuration.